EXTENSION TO 3RD-ORDER CORIOLIS TERMS OF THE ANALYSIS OF V10-LEVEL, V7-LEVEL, AND V4-LEVEL OF ETHYLENE ON THE BASIS OF FOURIER-TRANSFORM AND DIODE-LASER SPECTRA

The ν7, ν10, and ν4 levels of ethylene have been studied based on waveguide laser, Fourier transform, and diode laser spectra in the range from 798 to 1091 cm-1. The absolute calibration of these spectra is better than 0.0002 cm-1. To deal with so many and so accurate experimental data, we have developed in our analysis programs the Watson Hamiltonian up to the sextic centrifugal distortion coefficients and the interaction Hamiltonian up to the third-order Coriolis resonance terms. The molecular parameters of the vibrational ground state have been significantly improved on the basis of more than 4000 GSCD. In the analysis of ν7, ν10, and ν4 levels, we had to introduce the ν12 level, which contributes to the indirect coupling of ν7 and ν4 through strong Coriolis interactions. We obtain a statistical agreement with all experimental data with an estimated standard deviation equal to 0.84. The intrinsic intensity of the ν10 band has been determined to be 16 500 ± 2500 times lower than the intensity of the ν7 band. © 1990.